Stephen J Sharkey

US Patent:

42271991, Oct 7, 1980

Filed:

May 9, 1979

Appl. No.:

6/037558

Inventors:

Stephen R. Sharkey - Lawrence NY

International Classification:

G01D 900

US Classification:

346 11

Abstract:

A double check or safety system for recording information of two types on a record sheet, such as a time clock card. One type of information is applied automatically to a first predetermined area of the record sheet when the sheet is inserted into a machine, such as the entrance time and exit time stamped onto the record sheet by a time clock. The other type of information is applied manually by the operator, such as a signature applied by the operator to a second predetermined area of the record sheet associated with the time stamp area. The invention comprises the step of automatically wetting said second predetermined area with a color-forming chemical, either before or simultaneously with the automatic application of the said one type of information to the first predetermined area and thereafter manually applying said other type of information to said wetted area, such as by applying a written signature using a pen containing a complimentary liquid which is substantially colorless but which is reactive with said color-forming liquid, while the latter is in liquid state, to form a colored, legible reaction product in the form of an ink signature.